From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D8A85C25B76 for ; Tue, 11 Jun 2024 08:51:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=3C2tEHdGA2v7VhPPGzNtOblR2H1A58bgSO3ipOOgj38=; b=tRONcDYfOwVLzL SJALqIqaJJ3iJXlFO3IlrMrN6GBgQE+aRXR6ko3ZKfPxRxeh5SKIF7xSZEWdr2zLIluzd9UJawjZN X+XL/0HlcxopmeMIXnD/WI4zrUVEmhc6R2PkFbr856hvf5iv3RTtyB4lfzHmZgZlNPSQwgxbg9rV9 f+iu47MjCLWehUCneN3KSD/UY+TqE5GNsHJ+EkVikVDijyBFZ48T7U7xNIeIWpiY1eQ3WMqGtc58O PN1vKxS7Mow+GuwHHBo6kkqWkPG2lscSII7DWX6+OmXuHbJ1Jg8pedUyDrgw53V0VJ3uV/zmbbk9y VQ+oCLDK0akXUKhdcgnw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sGxDP-00000008Bgr-17sN; Tue, 11 Jun 2024 08:50:51 +0000 Received: from elvis.franken.de ([193.175.24.41]) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sGxDJ-00000008Bdn-1uUf; Tue, 11 Jun 2024 08:50:48 +0000 Received: from uucp by elvis.franken.de with local-rmail (Exim 3.36 #1) id 1sGxBT-0000Ne-00; Tue, 11 Jun 2024 10:48:51 +0200 Received: by alpha.franken.de (Postfix, from userid 1000) id 023C9C0120; Tue, 11 Jun 2024 10:41:16 +0200 (CEST) Date: Tue, 11 Jun 2024 10:41:16 +0200 From: Thomas Bogendoerfer To: Celeste Liu Cc: Heinrich Schuchardt , Anup Patel , Guo Ren , Palmer Dabbelt , Paul Walmsley , Huacai Chen , WANG Xuerui , Vladimir Kondratiev , Gregory CLEMENT , =?iso-8859-1?Q?Th=E9o?= Lebrun , Michael Ellerman , Nicholas Piggin , Christophe Leroy , "Naveen N . Rao" , Sven Joachim , Yoshinori Sato , Rich Felker , John Paul Adrian Glaubitz , Russell King , Florian Fainelli , Ray Jui , Scott Branden , Broadcom internal kernel review list , Tony Lindgren , Thierry Reding , Jonathan Hunter , Arnd Bergmann , Mykola Lysenko , linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-rpi-kernel@lists.infradead.org, linux-omap@vger.kernel.org, linux-tegra@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-sh@vger.kernel.org, linux-kselftest@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, Lennart Poettering , Icenowy Zheng Subject: Re: [PATCH 3/6] mips: defconfig: drop RT_GROUP_SCHED=y from generic/db1xxx/eyeq5 Message-ID: References: <20240530111947.549474-8-CoelacanthusHex@gmail.com> <20240530111947.549474-11-CoelacanthusHex@gmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20240530111947.549474-11-CoelacanthusHex@gmail.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240611_015045_993901_58636937 X-CRM114-Status: GOOD ( 16.97 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, May 30, 2024 at 07:19:51PM +0800, Celeste Liu wrote: > For cgroup v1, if turned on, and there's any cgroup in the "cpu" hierarchy it > needs an RT budget assigned, otherwise the processes in it will not be able to > get RT at all. The problem with RT group scheduling is that it requires the > budget assigned but there's no way we could assign a default budget, since the > values to assign are both upper and lower time limits, are absolute, and need to > be sum up to < 1 for each individal cgroup. That means we cannot really come up > with values that would work by default in the general case.[1] > > For cgroup v2, it's almost unusable as well. If it turned on, the cpu controller > can only be enabled when all RT processes are in the root cgroup. But it will > lose the benefits of cgroup v2 if all RT process were placed in the same cgroup. > > Red Hat, Gentoo, Arch Linux and Debian all disable it. systemd also doesn't > support it.[2] > > [1]: https://bugzilla.redhat.com/show_bug.cgi?id=1229700 > [2]: https://github.com/systemd/systemd/issues/13781#issuecomment-549164383 > > Signed-off-by: Celeste Liu > --- > arch/mips/configs/db1xxx_defconfig | 1 - > arch/mips/configs/eyeq5_defconfig | 1 - > arch/mips/configs/generic_defconfig | 1 - > 3 files changed, 3 deletions(-) applied to mips-next. Thomas. -- Crap can work. Given enough thrust pigs will fly, but it's not necessarily a good idea. [ RFC1925, 2.3 ] _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel